// SPDX-License-Identifier: GPL-2.0+
/*
 * Procedures for creating, accessing and interpreting the device tree.
 *
 * Paul Mackerras	August 1996.
 * Copyright (C) 1996-2005 Paul Mackerras.
 *
 *  Adapted for 64bit PowerPC by Dave Engebretsen and Peter Bergner.
 *    {engebret|bergner}@us.ibm.com
 *
 *  Adapted for sparc and sparc64 by David S. Miller davem@davemloft.net
 *
 *  Reconsolidated from arch/x/kernel/prom.c by Stephen Rothwell and
 *  Grant Likely.
 */

#define pr_fmt(fmt)	"OF: " fmt

#include <seminix/kernel.h>
#include <seminix/ctype.h>
#include <seminix/string.h>
#include <seminix/of.h>
#include <seminix/cpumask.h>
#include <seminix/mutex.h>
#include <seminix/slab.h>
#include <seminix/cpu.h>
#include "of_private.h"

LIST_HEAD(aliases_lookup);

struct device_node *of_root;
struct device_node *of_chosen;
struct device_node *of_aliases;
struct device_node *of_stdout;
static const char *of_stdout_options;

/*
 * Used to protect the of_aliases, to hold off addition of nodes to sysfs.
 * This mutex must be held whenever modifications are being made to the
 * device tree. The of_{attach,detach}_node() and
 * of_{add,remove,update}_property() helpers make sure this happens.
 */
static DEFINE_MUTEX(of_mutex);

/* use when traversing tree through the child, sibling,
 * or parent members of struct device_node.
 */
DEFINE_RAW_SPINLOCK(devtree_lock);

bool of_node_name_eq(const struct device_node *np, const char *name)
{
    const char *node_name;
    usize len;

    if (!np)
        return false;

    node_name = kbasename(np->full_name);
    len = strchrnul(node_name, '@') - node_name;

    return (strlen(name) == len) && (strncmp(node_name, name, len) == 0);
}

bool of_node_name_prefix(const struct device_node *np, const char *prefix)
{
    if (!np)
        return false;

    return strncmp(kbasename(np->full_name), prefix, strlen(prefix)) == 0;
}

static bool __of_node_is_type(const struct device_node *np, const char *type)
{
    const char *match = __of_get_property(np, "device_type", NULL);

    return np && match && type && !strcmp(match, type);
}

int of_n_addr_cells(struct device_node *np)
{
    u32 cells;

    do {
        if (np->parent)
            np = np->parent;
        if (!of_property_read_u32(np, "#address-cells", &cells))
            return cells;
    } while (np->parent);
    /* No #address-cells property for the root node */
    return OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
}

int of_n_size_cells(struct device_node *np)
{
    u32 cells;

    do {
        if (np->parent)
            np = np->parent;
        if (!of_property_read_u32(np, "#size-cells", &cells))
            return cells;
    } while (np->parent);
    /* No #size-cells property for the root node */
    return OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
}

/*
 * Assumptions behind phandle_cache implementation:
 *   - phandle property values are in a contiguous range of 1..n
 *
 * If the assumptions do not hold, then
 *   - the phandle lookup overhead reduction provided by the cache
 *     will likely be less
 */

static struct device_node **phandle_cache;
static u32 phandle_cache_mask;

/*
 * Caller must hold devtree_lock.
 */
static void __of_free_phandle_cache(void)
{
    if (!phandle_cache)
        return;

    kfree(phandle_cache);
    phandle_cache = NULL;
}

int of_free_phandle_cache(void)
{
    unsigned long flags;

    raw_spin_lock_irqsave(&devtree_lock, flags);

    __of_free_phandle_cache();

    raw_spin_unlock_irqrestore(&devtree_lock, flags);

    return 0;
}

void of_populate_phandle_cache(void)
{
    unsigned long flags;
    u32 cache_entries;
    struct device_node *np;
    u32 phandles = 0;

    raw_spin_lock_irqsave(&devtree_lock, flags);

    for_each_of_allnodes(np)
        if (np->phandle && np->phandle != OF_PHANDLE_ILLEGAL)
            phandles++;

    if (!phandles)
        goto out;

    cache_entries = roundup_pow_of_two(phandles);
    phandle_cache_mask = cache_entries - 1;

    phandle_cache = kcalloc(cache_entries, sizeof(*phandle_cache),
                GFP_KERNEL);
    if (!phandle_cache)
        goto out;

    for_each_of_allnodes(np)
        if (np->phandle && np->phandle != OF_PHANDLE_ILLEGAL)
            phandle_cache[np->phandle & phandle_cache_mask] = np;

out:
    raw_spin_unlock_irqrestore(&devtree_lock, flags);
}

static struct property *__of_find_property(const struct device_node *np,
                       const char *name, int *lenp)
{
    struct property *pp;

    if (!np)
        return NULL;

    for (pp = np->properties; pp; pp = pp->next) {
        if (of_prop_cmp(pp->name, name) == 0) {
            if (lenp)
                *lenp = pp->length;
            break;
        }
    }

    return pp;
}

struct property *of_find_property(const struct device_node *np,
                  const char *name,
                  int *lenp)
{
    struct property *pp;
    unsigned long flags;

    raw_spin_lock_irqsave(&devtree_lock, flags);
    pp = __of_find_property(np, name, lenp);
    raw_spin_unlock_irqrestore(&devtree_lock, flags);

    return pp;
}

struct device_node *__of_find_all_nodes(struct device_node *prev)
{
    struct device_node *np;
    if (!prev) {
        np = of_root;
    } else if (prev->child) {
        np = prev->child;
    } else {
        /* Walk back up looking for a sibling, or the end of the structure */
        np = prev;
        while (np->parent && !np->sibling)
            np = np->parent;
        np = np->sibling; /* Might be null at the end of the tree */
    }
    return np;
}

/**
 * of_find_all_nodes - Get next node in global list
 * @prev:	Previous node or NULL to start iteration
 *		of_node_put() will be called on it
 *
 * Returns a node pointer with refcount incremented, use
 * of_node_put() on it when done.
 */
struct device_node *of_find_all_nodes(struct device_node *prev)
{
    struct device_node *np;
    unsigned long flags;

    raw_spin_lock_irqsave(&devtree_lock, flags);
    np = __of_find_all_nodes(prev);
    raw_spin_unlock_irqrestore(&devtree_lock, flags);
    return np;
}

/*
 * Find a property with a given name for a given node
 * and return the value.
 */
const void *__of_get_property(const struct device_node *np,
                  const char *name, int *lenp)
{
    struct property *pp = __of_find_property(np, name, lenp);

    return pp ? pp->value : NULL;
}

/*
 * Find a property with a given name for a given node
 * and return the value.
 */
const void *of_get_property(const struct device_node *np, const char *name,
                int *lenp)
{
    struct property *pp = of_find_property(np, name, lenp);

    return pp ? pp->value : NULL;
}

/*
 * arch_match_cpu_phys_id - Match the given logical CPU and physical id
 *
 * @cpu: logical cpu index of a core/thread
 * @phys_id: physical identifier of a core/thread
 *
 * CPU logical to physical index mapping is architecture specific.
 * However this __weak function provides a default match of physical
 * id to logical cpu index. phys_id provided here is usually values read
 * from the device tree which must match the hardware internal registers.
 *
 * Returns true if the physical identifier and the logical cpu index
 * correspond to the same core/thread, false otherwise.
 */
bool __weak arch_match_cpu_phys_id(int cpu, u64 phys_id)
{
    return (int)phys_id == cpu;
}

/**
 * Checks if the given "prop_name" property holds the physical id of the
 * core/thread corresponding to the logical cpu 'cpu'. If 'thread' is not
 * NULL, local thread number within the core is returned in it.
 */
static bool __of_find_n_match_cpu_property(struct device_node *cpun,
            const char *prop_name, int cpu, unsigned int *thread)
{
    const __be32 *cell;
    int ac, prop_len, tid;
    u64 hwid;

    ac = of_n_addr_cells(cpun);
    cell = of_get_property(cpun, prop_name, &prop_len);
    if (!cell && !ac && arch_match_cpu_phys_id(cpu, 0))
        return true;
    if (!cell || !ac)
        return false;
    prop_len /= sizeof(*cell) * ac;
    for (tid = 0; tid < prop_len; tid++) {
        hwid = of_read_number(cell, ac);
        if (arch_match_cpu_phys_id(cpu, hwid)) {
            if (thread)
                *thread = tid;
            return true;
        }
        cell += ac;
    }
    return false;
}

/*
 * arch_find_n_match_cpu_physical_id - See if the given device node is
 * for the cpu corresponding to logical cpu 'cpu'.  Return true if so,
 * else false.  If 'thread' is non-NULL, the local thread number within the
 * core is returned in it.
 */
bool __weak arch_find_n_match_cpu_physical_id(struct device_node *cpun,
                          int cpu, unsigned int *thread)
{
    /* Check for non-standard "ibm,ppc-interrupt-server#s" property
     * for thread ids on PowerPC. If it doesn't exist fallback to
     * standard "reg" property.
     */
    if (IS_ENABLED(CONFIG_PPC) &&
        __of_find_n_match_cpu_property(cpun,
                       "ibm,ppc-interrupt-server#s",
                       cpu, thread))
        return true;

    return __of_find_n_match_cpu_property(cpun, "reg", cpu, thread);
}

/**
 * of_get_cpu_node - Get device node associated with the given logical CPU
 *
 * @cpu: CPU number(logical index) for which device node is required
 * @thread: if not NULL, local thread number within the physical core is
 *          returned
 *
 * The main purpose of this function is to retrieve the device node for the
 * given logical CPU index. It should be used to initialize the of_node in
 * cpu device. Once of_node in cpu device is populated, all the further
 * references can use that instead.
 *
 * CPU logical to physical index mapping is architecture specific and is built
 * before booting secondary cores. This function uses arch_match_cpu_phys_id
 * which can be overridden by architecture specific implementation.
 *
 * Returns a node pointer for the logical cpu with refcount incremented, use
 * of_node_put() on it when done. Returns NULL if not found.
 */
struct device_node *of_get_cpu_node(int cpu, unsigned int *thread)
{
    struct device_node *cpun;

    for_each_of_cpu_node(cpun) {
        if (arch_find_n_match_cpu_physical_id(cpun, cpu, thread))
            return cpun;
    }
    return NULL;
}

/**
 * of_cpu_node_to_id: Get the logical CPU number for a given device_node
 *
 * @cpu_node: Pointer to the device_node for CPU.
 *
 * Returns the logical CPU number of the given CPU device_node.
 * Returns -ENODEV if the CPU is not found.
 */
int of_cpu_node_to_id(struct device_node *cpu_node)
{
    int cpu;
    bool found = false;
    struct device_node *np;

    for_each_possible_cpu(cpu) {
        np = of_cpu_device_node_get(cpu);
        found = (cpu_node == np);
        if (found)
            return cpu;
    }

    return -ENODEV;
}

/**
 * __of_device_is_compatible() - Check if the node matches given constraints
 * @device: pointer to node
 * @compat: required compatible string, NULL or "" for any match
 * @type: required device_type value, NULL or "" for any match
 * @name: required node name, NULL or "" for any match
 *
 * Checks if the given @compat, @type and @name strings match the
 * properties of the given @device. A constraints can be skipped by
 * passing NULL or an empty string as the constraint.
 *
 * Returns 0 for no match, and a positive integer on match. The return
 * value is a relative score with larger values indicating better
 * matches. The score is weighted for the most specific compatible value
 * to get the highest score. Matching type is next, followed by matching
 * name. Practically speaking, this results in the following priority
 * order for matches:
 *
 * 1. specific compatible && type && name
 * 2. specific compatible && type
 * 3. specific compatible && name
 * 4. specific compatible
 * 5. general compatible && type && name
 * 6. general compatible && type
 * 7. general compatible && name
 * 8. general compatible
 * 9. type && name
 * 10. type
 * 11. name
 */
static int __of_device_is_compatible(const struct device_node *device,
                     const char *compat, const char *type, const char *name)
{
    struct property *prop;
    const char *cp;
    int index = 0, score = 0;

    /* Compatible match has highest priority */
    if (compat && compat[0]) {
        prop = __of_find_property(device, "compatible", NULL);
        for (cp = of_prop_next_string(prop, NULL); cp;
             cp = of_prop_next_string(prop, cp), index++) {
            if (of_compat_cmp(cp, compat, strlen(compat)) == 0) {
                score = INT_MAX/2 - (index << 2);
                break;
            }
        }
        if (!score)
            return 0;
    }

    /* Matching type is better than matching name */
    if (type && type[0]) {
        if (!__of_node_is_type(device, type))
            return 0;
        score += 2;
    }

    /* Matching name is a bit better than not */
    if (name && name[0]) {
        if (!of_node_name_eq(device, name))
            return 0;
        score++;
    }

    return score;
}

/** Checks if the given "compat" string matches one of the strings in
 * the device's "compatible" property
 */
int of_device_is_compatible(const struct device_node *device,
        const char *compat)
{
    unsigned long flags;
    int res;

    raw_spin_lock_irqsave(&devtree_lock, flags);
    res = __of_device_is_compatible(device, compat, NULL, NULL);
    raw_spin_unlock_irqrestore(&devtree_lock, flags);
    return res;
}

/** Checks if the device is compatible with any of the entries in
 *  a NULL terminated array of strings. Returns the best match
 *  score or 0.
 */
int of_device_compatible_match(struct device_node *device,
                   const char *const *compat)
{
    unsigned int tmp, score = 0;

    if (!compat)
        return 0;

    while (*compat) {
        tmp = of_device_is_compatible(device, *compat);
        if (tmp > score)
            score = tmp;
        compat++;
    }

    return score;
}

/**
 * of_machine_is_compatible - Test root of device tree for a given compatible value
 * @compat: compatible string to look for in root node's compatible property.
 *
 * Returns a positive integer if the root node has the given value in its
 * compatible property.
 */
int of_machine_is_compatible(const char *compat)
{
    struct device_node *root;
    int rc = 0;

    root = of_find_node_by_path("/");
    if (root)
        rc = of_device_is_compatible(root, compat);

    return rc;
}

/**
 *  __of_device_is_available - check if a device is available for use
 *
 *  @device: Node to check for availability, with locks already held
 *
 *  Returns true if the status property is absent or set to "okay" or "ok",
 *  false otherwise
 */
static bool __of_device_is_available(const struct device_node *device)
{
    const char *status;
    int statlen;

    if (!device)
        return false;

    status = __of_get_property(device, "status", &statlen);
    if (status == NULL)
        return true;

    if (statlen > 0) {
        if (!strcmp(status, "okay") || !strcmp(status, "ok"))
            return true;
    }

    return false;
}

/**
 *  of_device_is_available - check if a device is available for use
 *
 *  @device: Node to check for availability
 *
 *  Returns true if the status property is absent or set to "okay" or "ok",
 *  false otherwise
 */
bool of_device_is_available(const struct device_node *device)
{
    unsigned long flags;
    bool res;

    raw_spin_lock_irqsave(&devtree_lock, flags);
    res = __of_device_is_available(device);
    raw_spin_unlock_irqrestore(&devtree_lock, flags);
    return res;

}

/**
 *  of_device_is_big_endian - check if a device has BE registers
 *
 *  @device: Node to check for endianness
 *
 *  Returns true if the device has a "big-endian" property, or if the kernel
 *  was compiled for BE *and* the device has a "native-endian" property.
 *  Returns false otherwise.
 *
 *  Callers would nominally use ioread32be/iowrite32be if
 *  of_device_is_big_endian() == true, or readl/writel otherwise.
 */
bool of_device_is_big_endian(const struct device_node *device)
{
    if (of_property_read_bool(device, "big-endian"))
        return true;
    if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) &&
        of_property_read_bool(device, "native-endian"))
        return true;
    return false;
}

/**
 *	of_get_parent - Get a node's parent if any
 *	@node:	Node to get parent
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_get_parent(const struct device_node *node)
{
    struct device_node *np;
    unsigned long flags;

    if (!node)
        return NULL;

    raw_spin_lock_irqsave(&devtree_lock, flags);
    np = node->parent;
    raw_spin_unlock_irqrestore(&devtree_lock, flags);
    return np;
}

/**
 *	of_get_next_parent - Iterate to a node's parent
 *	@node:	Node to get parent of
 *
 *	This is like of_get_parent() except that it drops the
 *	refcount on the passed node, making it suitable for iterating
 *	through a node's parents.
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_get_next_parent(struct device_node *node)
{
    struct device_node *parent;
    unsigned long flags;

    if (!node)
        return NULL;

    raw_spin_lock_irqsave(&devtree_lock, flags);
    parent = node->parent;
    raw_spin_unlock_irqrestore(&devtree_lock, flags);
    return parent;
}

static struct device_node *__of_get_next_child(const struct device_node *node,
                        struct device_node *prev)
{
    struct device_node *next;

    if (!node)
        return NULL;

    next = prev ? prev->sibling : node->child;
    for (; next; next = next->sibling)
        if (next)
            break;

    return next;
}
#define __for_each_child_of_node(parent, child) \
    for (child = __of_get_next_child(parent, NULL); child != NULL; \
         child = __of_get_next_child(parent, child))

/**
 *	of_get_next_child - Iterate a node childs
 *	@node:	parent node
 *	@prev:	previous child of the parent node, or NULL to get first
 *
 *	Returns a node pointer with refcount incremented, use of_node_put() on
 *	it when done. Returns NULL when prev is the last child. Decrements the
 *	refcount of prev.
 */
struct device_node *of_get_next_child(const struct device_node *node,
    struct device_node *prev)
{
    struct device_node *next;
    unsigned long flags;

    raw_spin_lock_irqsave(&devtree_lock, flags);
    next = __of_get_next_child(node, prev);
    raw_spin_unlock_irqrestore(&devtree_lock, flags);
    return next;
}

/**
 *	of_get_next_available_child - Find the next available child node
 *	@node:	parent node
 *	@prev:	previous child of the parent node, or NULL to get first
 *
 *      This function is like of_get_next_child(), except that it
 *      automatically skips any disabled nodes (i.e. status = "disabled").
 */
struct device_node *of_get_next_available_child(const struct device_node *node,
    struct device_node *prev)
{
    struct device_node *next;
    unsigned long flags;

    if (!node)
        return NULL;

    raw_spin_lock_irqsave(&devtree_lock, flags);
    next = prev ? prev->sibling : node->child;
    for (; next; next = next->sibling) {
        if (!__of_device_is_available(next))
            continue;
        if (next)
            break;
    }

    raw_spin_unlock_irqrestore(&devtree_lock, flags);
    return next;
}

/**
 *	of_get_next_cpu_node - Iterate on cpu nodes
 *	@prev:	previous child of the /cpus node, or NULL to get first
 *
 *	Returns a cpu node pointer with refcount incremented, use of_node_put()
 *	on it when done. Returns NULL when prev is the last child. Decrements
 *	the refcount of prev.
 */
struct device_node *of_get_next_cpu_node(struct device_node *prev)
{
    struct device_node *next = NULL;
    unsigned long flags;
    struct device_node *node;

    if (!prev)
        node = of_find_node_by_path("/cpus");

    raw_spin_lock_irqsave(&devtree_lock, flags);
    if (prev)
        next = prev->sibling;
    else if (node) {
        next = node->child;
    }
    for (; next; next = next->sibling) {
        if (!(of_node_name_eq(next, "cpu") ||
              __of_node_is_type(next, "cpu")))
            continue;
        if (next)
            break;
    }
    raw_spin_unlock_irqrestore(&devtree_lock, flags);
    return next;
}

/**
 * of_get_compatible_child - Find compatible child node
 * @parent:	parent node
 * @compatible:	compatible string
 *
 * Lookup child node whose compatible property contains the given compatible
 * string.
 *
 * Returns a node pointer with refcount incremented, use of_node_put() on it
 * when done; or NULL if not found.
 */
struct device_node *of_get_compatible_child(const struct device_node *parent,
                const char *compatible)
{
    struct device_node *child;

    for_each_child_of_node(parent, child) {
        if (of_device_is_compatible(child, compatible))
            break;
    }

    return child;
}

/**
 *	of_get_child_by_name - Find the child node by name for a given parent
 *	@node:	parent node
 *	@name:	child name to look for.
 *
 *      This function looks for child node for given matching name
 *
 *	Returns a node pointer if found, with refcount incremented, use
 *	of_node_put() on it when done.
 *	Returns NULL if node is not found.
 */
struct device_node *of_get_child_by_name(const struct device_node *node,
                const char *name)
{
    struct device_node *child;

    for_each_child_of_node(node, child)
        if (of_node_name_eq(child, name))
            break;
    return child;
}

struct device_node *__of_find_node_by_path(struct device_node *parent,
                        const char *path)
{
    struct device_node *child;
    int len;

    len = strcspn(path, "/:");
    if (!len)
        return NULL;

    __for_each_child_of_node(parent, child) {
        const char *name = kbasename(child->full_name);
        if (strncmp(path, name, len) == 0 && ((int)strlen(name) == len))
            return child;
    }
    return NULL;
}

struct device_node *__of_find_node_by_full_path(struct device_node *node,
                        const char *path)
{
    const char *separator = strchr(path, ':');

    while (node && *path == '/') {
        path++; /* Increment past '/' delimiter */
        node = __of_find_node_by_path(node, path);
        path = strchrnul(path, '/');
        if (separator && separator < path)
            break;
    }
    return node;
}

/**
 *	of_find_node_opts_by_path - Find a node matching a full OF path
 *	@path: Either the full path to match, or if the path does not
 *	       start with '/', the name of a property of the /aliases
 *	       node (an alias).  In the case of an alias, the node
 *	       matching the alias' value will be returned.
 *	@opts: Address of a pointer into which to store the start of
 *	       an options string appended to the end of the path with
 *	       a ':' separator.
 *
 *	Valid paths:
 *		/foo/bar	Full path
 *		foo		Valid alias
 *		foo/bar		Valid alias + relative path
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_find_node_opts_by_path(const char *path, const char **opts)
{
    struct device_node *np = NULL;
    struct property *pp;
    unsigned long flags;
    const char *separator = strchr(path, ':');

    if (opts)
        *opts = separator ? separator + 1 : NULL;

    if (strcmp(path, "/") == 0)
        return of_root;

    /* The path could begin with an alias */
    if (*path != '/') {
        int len;
        const char *p = separator;

        if (!p)
            p = strchrnul(path, '/');
        len = p - path;

        /* of_aliases must not be NULL */
        if (!of_aliases)
            return NULL;

        for_each_property_of_node(of_aliases, pp) {
            if ((int)strlen(pp->name) == len && !strncmp(pp->name, path, len)) {
                np = of_find_node_by_path(pp->value);
                break;
            }
        }
        if (!np)
            return NULL;
        path = p;
    }

    /* Step down the tree matching path components */
    raw_spin_lock_irqsave(&devtree_lock, flags);
    if (!np)
        np = of_root;
    np = __of_find_node_by_full_path(np, path);
    raw_spin_unlock_irqrestore(&devtree_lock, flags);
    return np;
}

/**
 *	of_find_node_by_name - Find a node by its "name" property
 *	@from:	The node to start searching from or NULL; the node
 *		you pass will not be searched, only the next one
 *		will. Typically, you pass what the previous call
 *		returned. of_node_put() will be called on @from.
 *	@name:	The name string to match against
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_find_node_by_name(struct device_node *from,
    const char *name)
{
    struct device_node *np;
    unsigned long flags;

    raw_spin_lock_irqsave(&devtree_lock, flags);
    for_each_of_allnodes_from(from, np)
        if (of_node_name_eq(np, name) && np)
            break;

    raw_spin_unlock_irqrestore(&devtree_lock, flags);
    return np;
}

/**
 *	of_find_node_by_type - Find a node by its "device_type" property
 *	@from:	The node to start searching from, or NULL to start searching
 *		the entire device tree. The node you pass will not be
 *		searched, only the next one will; typically, you pass
 *		what the previous call returned. of_node_put() will be
 *		called on from for you.
 *	@type:	The type string to match against
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_find_node_by_type(struct device_node *from,
    const char *type)
{
    struct device_node *np;
    unsigned long flags;

    raw_spin_lock_irqsave(&devtree_lock, flags);
    for_each_of_allnodes_from(from, np)
        if (__of_node_is_type(np, type) && np)
            break;

    raw_spin_unlock_irqrestore(&devtree_lock, flags);
    return np;
}

/**
 *	of_find_compatible_node - Find a node based on type and one of the
 *                                tokens in its "compatible" property
 *	@from:		The node to start searching from or NULL, the node
 *			you pass will not be searched, only the next one
 *			will; typically, you pass what the previous call
 *			returned. of_node_put() will be called on it
 *	@type:		The type string to match "device_type" or NULL to ignore
 *	@compatible:	The string to match to one of the tokens in the device
 *			"compatible" list.
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_find_compatible_node(struct device_node *from,
    const char *type, const char *compatible)
{
    struct device_node *np;
    unsigned long flags;

    raw_spin_lock_irqsave(&devtree_lock, flags);
    for_each_of_allnodes_from(from, np)
        if (__of_device_is_compatible(np, compatible, type, NULL) &&
            np)
            break;

    raw_spin_unlock_irqrestore(&devtree_lock, flags);
    return np;
}

/**
 *	of_find_node_with_property - Find a node which has a property with
 *                                   the given name.
 *	@from:		The node to start searching from or NULL, the node
 *			you pass will not be searched, only the next one
 *			will; typically, you pass what the previous call
 *			returned. of_node_put() will be called on it
 *	@prop_name:	The name of the property to look for.
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_find_node_with_property(struct device_node *from,
    const char *prop_name)
{
    struct device_node *np;
    struct property *pp;
    unsigned long flags;

    raw_spin_lock_irqsave(&devtree_lock, flags);
    for_each_of_allnodes_from(from, np) {
        for (pp = np->properties; pp; pp = pp->next) {
            if (of_prop_cmp(pp->name, prop_name) == 0) {
                goto out;
            }
        }
    }
out:
    raw_spin_unlock_irqrestore(&devtree_lock, flags);
    return np;
}

static
const struct of_device_id *__of_match_node(const struct of_device_id *matches,
                       const struct device_node *node)
{
    const struct of_device_id *best_match = NULL;
    int score, best_score = 0;

    if (!matches)
        return NULL;

    for (; matches->name[0] || matches->type[0] || matches->compatible[0]; matches++) {
        score = __of_device_is_compatible(node, matches->compatible,
                          matches->type, matches->name);
        if (score > best_score) {
            best_match = matches;
            best_score = score;
        }
    }

    return best_match;
}

/**
 * of_match_node - Tell if a device_node has a matching of_match structure
 *	@matches:	array of of device match structures to search in
 *	@node:		the of device structure to match against
 *
 *	Low level utility function used by device matching.
 */
const struct of_device_id *of_match_node(const struct of_device_id *matches,
                     const struct device_node *node)
{
    const struct of_device_id *match;
    unsigned long flags;

    raw_spin_lock_irqsave(&devtree_lock, flags);
    match = __of_match_node(matches, node);
    raw_spin_unlock_irqrestore(&devtree_lock, flags);
    return match;
}

/**
 *	of_find_matching_node_and_match - Find a node based on an of_device_id
 *					  match table.
 *	@from:		The node to start searching from or NULL, the node
 *			you pass will not be searched, only the next one
 *			will; typically, you pass what the previous call
 *			returned. of_node_put() will be called on it
 *	@matches:	array of of device match structures to search in
 *	@match		Updated to point at the matches entry which matched
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.
 */
struct device_node *of_find_matching_node_and_match(struct device_node *from,
                    const struct of_device_id *matches,
                    const struct of_device_id **match)
{
    struct device_node *np;
    const struct of_device_id *m;
    unsigned long flags;

    if (match)
        *match = NULL;

    raw_spin_lock_irqsave(&devtree_lock, flags);
    for_each_of_allnodes_from(from, np) {
        m = __of_match_node(matches, np);
        if (m && np) {
            if (match)
                *match = m;
            break;
        }
    }
    raw_spin_unlock_irqrestore(&devtree_lock, flags);
    return np;
}

/**
 * of_modalias_node - Lookup appropriate modalias for a device node
 * @node:	pointer to a device tree node
 * @modalias:	Pointer to buffer that modalias value will be copied into
 * @len:	Length of modalias value
 *
 * Based on the value of the compatible property, this routine will attempt
 * to choose an appropriate modalias value for a particular device tree node.
 * It does this by stripping the manufacturer prefix (as delimited by a ',')
 * from the first entry in the compatible list property.
 *
 * This routine returns 0 on success, <0 on failure.
 */
int of_modalias_node(struct device_node *node, char *modalias, int len)
{
    const char *compatible, *p;
    int cplen;

    compatible = of_get_property(node, "compatible", &cplen);
    if (!compatible || (int)strlen(compatible) > cplen)
        return -ENODEV;
    p = strchr(compatible, ',');
    strlcpy(modalias, p ? p + 1 : compatible, len);
    return 0;
}

/**
 * of_find_node_by_phandle - Find a node given a phandle
 * @handle:	phandle of the node to find
 *
 * Returns a node pointer with refcount incremented, use
 * of_node_put() on it when done.
 */
struct device_node *of_find_node_by_phandle(phandle handle)
{
    struct device_node *np = NULL;
    unsigned long flags;
    phandle masked_handle;

    if (!handle)
        return NULL;

    raw_spin_lock_irqsave(&devtree_lock, flags);

    masked_handle = handle & phandle_cache_mask;

    if (phandle_cache) {
        if (phandle_cache[masked_handle] &&
            handle == phandle_cache[masked_handle]->phandle)
            np = phandle_cache[masked_handle];
        if (np && of_node_check_flag(np, OF_DETACHED)) {
            WARN_ON(1); /* did not uncache np on node removal */
            phandle_cache[masked_handle] = NULL;
            np = NULL;
        }
    }

    if (!np) {
        for_each_of_allnodes(np)
            if (np->phandle == handle &&
                !of_node_check_flag(np, OF_DETACHED)) {
                if (phandle_cache) {
                    /* will put when removed from cache */
                    phandle_cache[masked_handle] = np;
                }
                break;
            }
    }

    raw_spin_unlock_irqrestore(&devtree_lock, flags);
    return np;
}

void of_print_phandle_args(const char *msg, const struct of_phandle_args *args)
{
    int i;
    printk("%s %pOF", msg, args->np);
    for (i = 0; i < args->args_count; i++) {
        const char delim = i ? ',' : ':';

        pr_cont("%c%08x", delim, args->args[i]);
    }
    pr_cont("\n");
}

int of_phandle_iterator_init(struct of_phandle_iterator *it,
        const struct device_node *np,
        const char *list_name,
        const char *cells_name,
        int cell_count)
{
    const __be32 *list;
    int size;

    memset(it, 0, sizeof(*it));

    list = of_get_property(np, list_name, &size);
    if (!list)
        return -ENOENT;

    it->cells_name = cells_name;
    it->cell_count = cell_count;
    it->parent = np;
    it->list_end = list + size / sizeof(*list);
    it->phandle_end = list;
    it->cur = list;

    return 0;
}

int of_phandle_iterator_next(struct of_phandle_iterator *it)
{
    u32 count = 0;

    if (it->node) {
        it->node = NULL;
    }

    if (!it->cur || it->phandle_end >= it->list_end)
        return -ENOENT;

    it->cur = it->phandle_end;

    /* If phandle is 0, then it is an empty entry with no arguments. */
    it->phandle = be32_to_cpup(it->cur++);

    if (it->phandle) {

        /*
         * Find the provider node and parse the #*-cells property to
         * determine the argument length.
         */
        it->node = of_find_node_by_phandle(it->phandle);

        if (it->cells_name) {
            if (!it->node) {
                pr_err("%pOF: could not find phandle\n",
                       it->parent);
                goto err;
            }

            if (of_property_read_u32(it->node, it->cells_name,
                         &count)) {
                pr_err("%pOF: could not get %s for %pOF\n",
                       it->parent,
                       it->cells_name,
                       it->node);
                goto err;
            }
        } else {
            count = it->cell_count;
        }

        /*
         * Make sure that the arguments actually fit in the remaining
         * property data length
         */
        if (it->cur + count > it->list_end) {
            pr_err("%pOF: arguments longer than property\n",
                   it->parent);
            goto err;
        }
    }

    it->phandle_end = it->cur + count;
    it->cur_count = count;

    return 0;

err:
    if (it->node) {
        it->node = NULL;
    }

    return -EINVAL;
}

int of_phandle_iterator_args(struct of_phandle_iterator *it,
                 u32 *args,
                 int size)
{
    int i, count;

    count = it->cur_count;

    if (WARN_ON(size < count))
        count = size;

    for (i = 0; i < count; i++)
        args[i] = be32_to_cpup(it->cur++);

    return count;
}

static int __of_parse_phandle_with_args(const struct device_node *np,
                    const char *list_name,
                    const char *cells_name,
                    int cell_count, int index,
                    struct of_phandle_args *out_args)
{
    struct of_phandle_iterator it;
    int rc, cur_index = 0;

    /* Loop over the phandles until all the requested entry is found */
    of_for_each_phandle(&it, rc, np, list_name, cells_name, cell_count) {
        /*
         * All of the error cases bail out of the loop, so at
         * this point, the parsing is successful. If the requested
         * index matches, then fill the out_args structure and return,
         * or return -ENOENT for an empty entry.
         */
        rc = -ENOENT;
        if (cur_index == index) {
            if (!it.phandle)
                goto err;

            if (out_args) {
                int c;

                c = of_phandle_iterator_args(&it,
                                 out_args->args,
                                 MAX_PHANDLE_ARGS);
                out_args->np = it.node;
                out_args->args_count = c;
            }

            /* Found it! return success */
            return 0;
        }

        cur_index++;
    }

    /*
     * Unlock node before returning result; will be one of:
     * -ENOENT : index is for empty phandle
     * -EINVAL : parsing error on data
     */

 err:
    return rc;
}

/**
 * of_parse_phandle - Resolve a phandle property to a device_node pointer
 * @np: Pointer to device node holding phandle property
 * @phandle_name: Name of property holding a phandle value
 * @index: For properties holding a table of phandles, this is the index into
 *         the table
 *
 * Returns the device_node pointer with refcount incremented.  Use
 * of_node_put() on it when done.
 */
struct device_node *of_parse_phandle(const struct device_node *np,
                     const char *phandle_name, int index)
{
    struct of_phandle_args args;

    if (index < 0)
        return NULL;

    if (__of_parse_phandle_with_args(np, phandle_name, NULL, 0,
                     index, &args))
        return NULL;

    return args.np;
}

/**
 * of_parse_phandle_with_args() - Find a node pointed by phandle in a list
 * @np:		pointer to a device tree node containing a list
 * @list_name:	property name that contains a list
 * @cells_name:	property name that specifies phandles' arguments count
 * @index:	index of a phandle to parse out
 * @out_args:	optional pointer to output arguments structure (will be filled)
 *
 * This function is useful to parse lists of phandles and their arguments.
 * Returns 0 on success and fills out_args, on error returns appropriate
 * errno value.
 *
 * Caller is responsible to call of_node_put() on the returned out_args->np
 * pointer.
 *
 * Example:
 *
 * phandle1: node1 {
 *	#list-cells = <2>;
 * }
 *
 * phandle2: node2 {
 *	#list-cells = <1>;
 * }
 *
 * node3 {
 *	list = <&phandle1 1 2 &phandle2 3>;
 * }
 *
 * To get a device_node of the `node2' node you may call this:
 * of_parse_phandle_with_args(node3, "list", "#list-cells", 1, &args);
 */
int of_parse_phandle_with_args(const struct device_node *np, const char *list_name,
                const char *cells_name, int index,
                struct of_phandle_args *out_args)
{
    if (index < 0)
        return -EINVAL;
    return __of_parse_phandle_with_args(np, list_name, cells_name, 0,
                        index, out_args);
}

/**
 * of_parse_phandle_with_args_map() - Find a node pointed by phandle in a list and remap it
 * @np:		pointer to a device tree node containing a list
 * @list_name:	property name that contains a list
 * @stem_name:	stem of property names that specify phandles' arguments count
 * @index:	index of a phandle to parse out
 * @out_args:	optional pointer to output arguments structure (will be filled)
 *
 * This function is useful to parse lists of phandles and their arguments.
 * Returns 0 on success and fills out_args, on error returns appropriate errno
 * value. The difference between this function and of_parse_phandle_with_args()
 * is that this API remaps a phandle if the node the phandle points to has
 * a <@stem_name>-map property.
 *
 * Caller is responsible to call of_node_put() on the returned out_args->np
 * pointer.
 *
 * Example:
 *
 * phandle1: node1 {
 *	#list-cells = <2>;
 * }
 *
 * phandle2: node2 {
 *	#list-cells = <1>;
 * }
 *
 * phandle3: node3 {
 * 	#list-cells = <1>;
 * 	list-map = <0 &phandle2 3>,
 * 		   <1 &phandle2 2>,
 * 		   <2 &phandle1 5 1>;
 *	list-map-mask = <0x3>;
 * };
 *
 * node4 {
 *	list = <&phandle1 1 2 &phandle3 0>;
 * }
 *
 * To get a device_node of the `node2' node you may call this:
 * of_parse_phandle_with_args(node4, "list", "list", 1, &args);
 */
int of_parse_phandle_with_args_map(const struct device_node *np,
                   const char *list_name,
                   const char *stem_name,
                   int index, struct of_phandle_args *out_args)
{
    char *cells_name, *map_name = NULL, *mask_name = NULL;
    char *pass_name = NULL;
    struct device_node *cur, *new = NULL;
    const __be32 *map, *mask, *pass;
    static const __be32 dummy_mask[] = { [0 ... MAX_PHANDLE_ARGS] = ~0 };
    static const __be32 dummy_pass[] = { [0 ... MAX_PHANDLE_ARGS] = 0 };
    __be32 initial_match_array[MAX_PHANDLE_ARGS];
    const __be32 *match_array = initial_match_array;
    int i, ret, map_len, match;
    u32 list_size, new_size;

    if (index < 0)
        return -EINVAL;

    cells_name = kasprintf(GFP_KERNEL, "#%s-cells", stem_name);
    if (!cells_name)
        return -ENOMEM;

    ret = -ENOMEM;
    map_name = kasprintf(GFP_KERNEL, "%s-map", stem_name);
    if (!map_name)
        goto free;

    mask_name = kasprintf(GFP_KERNEL, "%s-map-mask", stem_name);
    if (!mask_name)
        goto free;

    pass_name = kasprintf(GFP_KERNEL, "%s-map-pass-thru", stem_name);
    if (!pass_name)
        goto free;

    ret = __of_parse_phandle_with_args(np, list_name, cells_name, 0, index,
                       out_args);
    if (ret)
        goto free;

    /* Get the #<list>-cells property */
    cur = out_args->np;
    ret = of_property_read_u32(cur, cells_name, &list_size);
    if (ret < 0)
        goto put;

    /* Precalculate the match array - this simplifies match loop */
    for (i = 0; i < (int)list_size; i++)
        initial_match_array[i] = cpu_to_be32(out_args->args[i]);

    ret = -EINVAL;
    while (cur) {
        /* Get the <list>-map property */
        map = of_get_property(cur, map_name, &map_len);
        if (!map) {
            ret = 0;
            goto free;
        }
        map_len /= sizeof(u32);

        /* Get the <list>-map-mask property (optional) */
        mask = of_get_property(cur, mask_name, NULL);
        if (!mask)
            mask = dummy_mask;
        /* Iterate through <list>-map property */
        match = 0;
        while (map_len > (int)(list_size + 1) && !match) {
            /* Compare specifiers */
            match = 1;
            for (i = 0; i < (int)list_size; i++, map_len--)
                match &= !((match_array[i] ^ *map++) & mask[i]);

            new = of_find_node_by_phandle(be32_to_cpup(map));
            map++;
            map_len--;

            /* Check if not found */
            if (!new)
                goto put;

            if (!of_device_is_available(new))
                match = 0;

            ret = of_property_read_u32(new, cells_name, &new_size);
            if (ret)
                goto put;

            /* Check for malformed properties */
            if (WARN_ON(new_size > MAX_PHANDLE_ARGS))
                goto put;
            if (map_len < (int)new_size)
                goto put;

            /* Move forward by new node's #<list>-cells amount */
            map += new_size;
            map_len -= new_size;
        }
        if (!match)
            goto put;

        /* Get the <list>-map-pass-thru property (optional) */
        pass = of_get_property(cur, pass_name, NULL);
        if (!pass)
            pass = dummy_pass;

        /*
         * Successfully parsed a <list>-map translation; copy new
         * specifier into the out_args structure, keeping the
         * bits specified in <list>-map-pass-thru.
         */
        match_array = map - new_size;
        for (i = 0; i < (int)new_size; i++) {
            __be32 val = *(map - new_size + i);

            if (i < (int)list_size) {
                val &= ~pass[i];
                val |= cpu_to_be32(out_args->args[i]) & pass[i];
            }

            out_args->args[i] = be32_to_cpu(val);
        }
        out_args->args_count = list_size = new_size;
        /* Iterate again with new provider */
        out_args->np = new;
        cur = new;
    }
put:
free:
    kfree(mask_name);
    kfree(map_name);
    kfree(cells_name);
    kfree(pass_name);

    return ret;
}

/**
 * of_parse_phandle_with_fixed_args() - Find a node pointed by phandle in a list
 * @np:		pointer to a device tree node containing a list
 * @list_name:	property name that contains a list
 * @cell_count: number of argument cells following the phandle
 * @index:	index of a phandle to parse out
 * @out_args:	optional pointer to output arguments structure (will be filled)
 *
 * This function is useful to parse lists of phandles and their arguments.
 * Returns 0 on success and fills out_args, on error returns appropriate
 * errno value.
 *
 * Caller is responsible to call of_node_put() on the returned out_args->np
 * pointer.
 *
 * Example:
 *
 * phandle1: node1 {
 * }
 *
 * phandle2: node2 {
 * }
 *
 * node3 {
 *	list = <&phandle1 0 2 &phandle2 2 3>;
 * }
 *
 * To get a device_node of the `node2' node you may call this:
 * of_parse_phandle_with_fixed_args(node3, "list", 2, 1, &args);
 */
int of_parse_phandle_with_fixed_args(const struct device_node *np,
                const char *list_name, int cell_count,
                int index, struct of_phandle_args *out_args)
{
    if (index < 0)
        return -EINVAL;
    return __of_parse_phandle_with_args(np, list_name, NULL, cell_count,
                       index, out_args);
}

/**
 * of_count_phandle_with_args() - Find the number of phandles references in a property
 * @np:		pointer to a device tree node containing a list
 * @list_name:	property name that contains a list
 * @cells_name:	property name that specifies phandles' arguments count
 *
 * Returns the number of phandle + argument tuples within a property. It
 * is a typical pattern to encode a list of phandle and variable
 * arguments into a single property. The number of arguments is encoded
 * by a property in the phandle-target node. For example, a gpios
 * property would contain a list of GPIO specifies consisting of a
 * phandle and 1 or more arguments. The number of arguments are
 * determined by the #gpio-cells property in the node pointed to by the
 * phandle.
 */
int of_count_phandle_with_args(const struct device_node *np, const char *list_name,
                const char *cells_name)
{
    struct of_phandle_iterator it;
    int rc, cur_index = 0;

    rc = of_phandle_iterator_init(&it, np, list_name, cells_name, 0);
    if (rc)
        return rc;

    while ((rc = of_phandle_iterator_next(&it)) == 0)
        cur_index += 1;

    if (rc != -ENOENT)
        return rc;

    return cur_index;
}

static void of_alias_add(struct alias_prop *ap, struct device_node *np,
             int id, const char *stem, int stem_len)
{
    ap->np = np;
    ap->id = id;
    strncpy(ap->stem, stem, stem_len);
    ap->stem[stem_len] = 0;
    list_add_tail(&ap->link, &aliases_lookup);
    pr_debug("adding DT alias:%s: stem=%s id=%i node=%pOF\n",
         ap->alias, ap->stem, ap->id, np);
}

/**
 * of_alias_scan - Scan all properties of the 'aliases' node
 *
 * The function scans all the properties of the 'aliases' node and populates
 * the global lookup table with the properties.  It returns the
 * number of alias properties found, or an error code in case of failure.
 *
 * @dt_alloc:	An allocator that provides a virtual address to memory
 *		for storing the resulting tree
 */
void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align))
{
    struct property *pp;

    of_aliases = of_find_node_by_path("/aliases");
    of_chosen = of_find_node_by_path("/chosen");
    if (of_chosen == NULL)
        of_chosen = of_find_node_by_path("/chosen@0");

    if (of_chosen) {
        /* linux,stdout-path and /aliases/stdout are for legacy compatibility */
        const char *name = NULL;

        if (of_property_read_string(of_chosen, "stdout-path", &name))
            of_property_read_string(of_chosen, "linux,stdout-path",
                        &name);
        if (IS_ENABLED(CONFIG_PPC) && !name)
            of_property_read_string(of_aliases, "stdout", &name);
        if (name)
            of_stdout = of_find_node_opts_by_path(name, &of_stdout_options);
    }

    if (!of_aliases)
        return;

    for_each_property_of_node(of_aliases, pp) {
        const char *start = pp->name;
        const char *end = start + strlen(start);
        struct device_node *np;
        struct alias_prop *ap;
        int id, len;

        /* Skip those we do not want to proceed */
        if (!strcmp(pp->name, "name") ||
            !strcmp(pp->name, "phandle") ||
            !strcmp(pp->name, "linux,phandle"))
            continue;

        np = of_find_node_by_path(pp->value);
        if (!np)
            continue;

        /* walk the alias backwards to extract the id and work out
         * the 'stem' string */
        while (isdigit(*(end-1)) && end > start)
            end--;
        len = end - start;

        if (kstrtoint(end, 10, &id) < 0)
            continue;

        /* Allocate an alias_prop with enough space for the stem */
        ap = dt_alloc(sizeof(*ap) + len + 1, __alignof__(*ap));
        if (!ap)
            continue;
        memset(ap, 0, sizeof(*ap) + len + 1);
        ap->alias = start;
        of_alias_add(ap, np, id, start, len);
    }
}

/**
 * of_alias_get_id - Get alias id for the given device_node
 * @np:		Pointer to the given device_node
 * @stem:	Alias stem of the given device_node
 *
 * The function travels the lookup table to get the alias id for the given
 * device_node and alias stem.  It returns the alias id if found.
 */
int of_alias_get_id(struct device_node *np, const char *stem)
{
    struct alias_prop *app;
    int id = -ENODEV;

    mutex_lock(&of_mutex);
    list_for_each_entry(app, &aliases_lookup, link) {
        if (strcmp(app->stem, stem) != 0)
            continue;

        if (np == app->np) {
            id = app->id;
            break;
        }
    }
    mutex_unlock(&of_mutex);

    return id;
}

/**
 * of_alias_get_alias_list - Get alias list for the given device driver
 * @matches:	Array of OF device match structures to search in
 * @stem:	Alias stem of the given device_node
 * @bitmap:	Bitmap field pointer
 * @nbits:	Maximum number of alias IDs which can be recorded in bitmap
 *
 * The function travels the lookup table to record alias ids for the given
 * device match structures and alias stem.
 *
 * Return:	0 or -ENOSYS when !CONFIG_OF or
 *		-EOVERFLOW if alias ID is greater then allocated nbits
 */
int of_alias_get_alias_list(const struct of_device_id *matches,
                 const char *stem, unsigned long *bitmap,
                 unsigned int nbits)
{
    struct alias_prop *app;
    int ret = 0;

    /* Zero bitmap field to make sure that all the time it is clean */
    bitmap_zero(bitmap, nbits);

    mutex_lock(&of_mutex);
    pr_debug("%s: Looking for stem: %s\n", __func__, stem);
    list_for_each_entry(app, &aliases_lookup, link) {
        pr_debug("%s: stem: %s, id: %d\n",
             __func__, app->stem, app->id);

        if (strcmp(app->stem, stem) != 0) {
            pr_debug("%s: stem comparison didn't pass %s\n",
                 __func__, app->stem);
            continue;
        }

        if (of_match_node(matches, app->np)) {
            pr_debug("%s: Allocated ID %d\n", __func__, app->id);

            if (app->id >= (int)nbits) {
                pr_warn("%s: ID %d >= than bitmap field %d\n",
                    __func__, app->id, nbits);
                ret = -EOVERFLOW;
            } else {
                set_bit(app->id, bitmap);
            }
        }
    }
    mutex_unlock(&of_mutex);

    return ret;
}

/**
 * of_alias_get_highest_id - Get highest alias id for the given stem
 * @stem:	Alias stem to be examined
 *
 * The function travels the lookup table to get the highest alias id for the
 * given alias stem.  It returns the alias id if found.
 */
int of_alias_get_highest_id(const char *stem)
{
    struct alias_prop *app;
    int id = -ENODEV;

    mutex_lock(&of_mutex);
    list_for_each_entry(app, &aliases_lookup, link) {
        if (strcmp(app->stem, stem) != 0)
            continue;

        if (app->id > id)
            id = app->id;
    }
    mutex_unlock(&of_mutex);

    return id;
}

/**
 * of_console_check() - Test and setup console for DT setup
 * @dn - Pointer to device node
 * @name - Name to use for preferred console without index. ex. "ttyS"
 * @index - Index to use for preferred console.
 *
 * Check if the given device node matches the stdout-path property in the
 * /chosen node. If it does then register it as the preferred console and return
 * TRUE. Otherwise return FALSE.
 */
const char *of_console_check(struct device_node *dn, char *name, int index)
{
    if (!dn || dn != of_stdout)
        return NULL;

    /*
     * XXX: cast `options' to char pointer to suppress complication
     * warnings: printk, UART and console drivers expect char pointer.
     */
    return of_stdout_options;
}

/**
 *	of_find_next_cache_node - Find a node's subsidiary cache
 *	@np:	node of type "cpu" or "cache"
 *
 *	Returns a node pointer with refcount incremented, use
 *	of_node_put() on it when done.  Caller should hold a reference
 *	to np.
 */
struct device_node *of_find_next_cache_node(const struct device_node *np)
{
    struct device_node *child, *cache_node;

    cache_node = of_parse_phandle(np, "l2-cache", 0);
    if (!cache_node)
        cache_node = of_parse_phandle(np, "next-level-cache", 0);

    if (cache_node)
        return cache_node;

    /* OF on pmac has nodes instead of properties named "l2-cache"
     * beneath CPU nodes.
     */
    if (IS_ENABLED(CONFIG_PPC_PMAC) && of_node_is_type(np, "cpu"))
        for_each_child_of_node(np, child)
            if (of_node_is_type(child, "cache"))
                return child;

    return NULL;
}

/**
 * of_find_last_cache_level - Find the level at which the last cache is
 * 		present for the given logical cpu
 *
 * @cpu: cpu number(logical index) for which the last cache level is needed
 *
 * Returns the the level at which the last cache is present. It is exactly
 * same as  the total number of cache levels for the given logical cpu.
 */
int of_find_last_cache_level(unsigned int cpu)
{
    u32 cache_level = 0;
    struct device_node *prev = NULL, *np = of_cpu_device_node_get(cpu);

    while (np) {
        prev = np;
        np = of_find_next_cache_node(np);
    }

    of_property_read_u32(prev, "cache-level", &cache_level);

    return cache_level;
}

/**
 * of_map_rid - Translate a requester ID through a downstream mapping.
 * @np: root complex device node.
 * @rid: device requester ID to map.
 * @map_name: property name of the map to use.
 * @map_mask_name: optional property name of the mask to use.
 * @target: optional pointer to a target device node.
 * @id_out: optional pointer to receive the translated ID.
 *
 * Given a device requester ID, look up the appropriate implementation-defined
 * platform ID and/or the target device which receives transactions on that
 * ID, as per the "iommu-map" and "msi-map" bindings. Either of @target or
 * @id_out may be NULL if only the other is required. If @target points to
 * a non-NULL device node pointer, only entries targeting that node will be
 * matched; if it points to a NULL value, it will receive the device node of
 * the first matching target phandle, with a reference held.
 *
 * Return: 0 on success or a standard error code on failure.
 */
int of_map_rid(struct device_node *np, u32 rid,
           const char *map_name, const char *map_mask_name,
           struct device_node **target, u32 *id_out)
{
    u32 map_mask, masked_rid;
    int map_len;
    const __be32 *map = NULL;

    if (!np || !map_name || (!target && !id_out))
        return -EINVAL;

    map = of_get_property(np, map_name, &map_len);
    if (!map) {
        if (target)
            return -ENODEV;
        /* Otherwise, no map implies no translation */
        *id_out = rid;
        return 0;
    }

    if (!map_len || map_len % (4 * sizeof(*map))) {
        pr_err("%pOF: Error: Bad %s length: %d\n", np,
            map_name, map_len);
        return -EINVAL;
    }

    /* The default is to select all bits. */
    map_mask = 0xffffffff;

    /*
     * Can be overridden by "{iommu,msi}-map-mask" property.
     * If of_property_read_u32() fails, the default is used.
     */
    if (map_mask_name)
        of_property_read_u32(np, map_mask_name, &map_mask);

    masked_rid = map_mask & rid;
    for ( ; map_len > 0; map_len -= 4 * sizeof(*map), map += 4) {
        struct device_node *phandle_node;
        u32 rid_base = be32_to_cpup(map + 0);
        u32 phandlei = be32_to_cpup(map + 1);
        u32 out_base = be32_to_cpup(map + 2);
        u32 rid_len = be32_to_cpup(map + 3);

        if (rid_base & ~map_mask) {
            pr_err("%pOF: Invalid %s translation - %s-mask (0x%x) ignores rid-base (0x%x)\n",
                np, map_name, map_name,
                map_mask, rid_base);
            return -EFAULT;
        }

        if (masked_rid < rid_base || masked_rid >= rid_base + rid_len)
            continue;

        phandle_node = of_find_node_by_phandle(phandlei);
        if (!phandle_node)
            return -ENODEV;

        if (target) {
            if (!*target)
                *target = phandle_node;

            if (*target != phandle_node)
                continue;
        }

        if (id_out)
            *id_out = masked_rid - rid_base + out_base;

        pr_debug("%pOF: %s, using mask %08x, rid-base: %08x, out-base: %08x, length: %08x, rid: %08x -> %08x\n",
            np, map_name, map_mask, rid_base, out_base,
            rid_len, rid, masked_rid - rid_base + out_base);
        return 0;
    }

    pr_err("%pOF: Invalid %s translation - no match for rid 0x%x on %pOF\n",
        np, map_name, rid, target && *target ? *target : NULL);
    return -EFAULT;
}
